Pet door flap frame



FIG. 1 is a front perspective view of a pet door flap frame showing mynew design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a side elevational view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof.

The ornamental design for a pet door flat frame, as shown and described.